The invention relates to a microwave vehicle-to-vehicle signaling device that uses an electronic warning signal impressed on a microwave signal in order to provide two-way communications among vehicles. The microwave signaling device transmits and receives warning signals, and provides electronic control signals for controlling visible and audible warning indications to the driver of a vehicle in response to the electronic warning signal.
One way to reduce traffic noise and improve the effectiveness of warning signals exchanged among vehicles is to equip each vehicle with a microwave vehicle-to-vehicle signaling device that is capable of both transmitting warning signals by means of a microwave signal and receiving warning signals from other vehicles by means of a microwave signal. The microwave vehicle-to-vehicle signaling device transforms received microwave signals into control signals that are suitable for controlling devices for producing sounds, for example the sound of an automobile horn that is generated by means of speakers arranged around a driver of a vehicle. The amplitude of the sound from each speaker is controlled by the signaling device in such a way as to provide an indication of the direction to the origin of the received warning signals. The amplitude and frequency of the sound from each speaker is also controlled by the signaling device in such a way as to provide an indication of the distances to vehicles that are transmitting warning signals. The sounds are generated within the vehicle at an amplitude that is inaudible or nearly inaudible outside of the vehicle. The microwave vehicle-to-vehicle signaling device also produces control signals that are suitable for controlling lamps or displays located within the field of view of the driver of each receiving vehicle, which provides assistance to drivers with hearing difficulties.
One object of the invention is to reduce or eliminate noise due to audible vehicle-to-vehicle signaling devices by confining most or all audible warning sounds, for example those produced by automobile horns, to the passenger compartment of each vehicle. The effective range of a warning signal transmission is limited by atmospheric absorption and by the transmitted signal power.
Another object of the invention is to provide control signals that are suitable for producing sounds within a vehicle by controlling a set of audio speakers or other sound producing devices in such a way as to allow the driver to determine the general directions and relative distances of microwave transmitters that are transmitting the warning signals.
Another object of the invention is to increase the effectiveness of audible police vehicle or emergency vehicle warning signals by reducing the ambient noise level in the environment. Alternatively, the invention allows a police vehicle or an emergency vehicle to reduce the amplitude of its audible vehicle-to-vehicle signaling device. The invention reduces the need for police and emergency vehicles to produce high amplitude audible warning signals, which are normally necessary to penetrate closed vehicles and compete with sound from music, conversation, and ambient traffic noise. The ambient traffic noise also includes automobile horn sounds, which would be reduced in amplitude by the invention. The microwave signals produced by the invention are inaudible to humans.
A further object of the invention is to limit the duty cycle and pulse repetition frequency of the microwave vehicle-to-vehicle signaling device, for example to prevent excessive use of the signaling device.
A system for producing automobile horn sounds by synthetic means is described by Solow (U.S. Pat. No. 6,489,885), where a digital counter responsive to clock signals from an oscillator sequentially reads horn audio data from digital memory, which provides the data to a D/A converter and the output audio signal to a speaker for broadcast. Farmer (U.S. Pat. No. 5,979,586) describes a vehicle collision warning system that converts collision threat messages from a predictive collision sensor into intuitive sounds which are perceived by the occupant to be directed from the direction of the potential collision. The collision threat messages are derived from a range sensing circuit, for example a radar set mounted in the vehicle, and they are not transmitted from a second vehicle. Settles (U.S. Pat. No. 5,933,074) describes a radio transmitter that operates in conjunction with a microwave (RF) receiver installed in a vehicle to unlock the doors of the vehicle when a unique RF signal is broadcast within a defined range, and actuate the horn of the vehicle when the same RF signal is broadcast outside of the defined range. The radio transmitter is hand held and is typically carried on a key chain, and it actuates an audible horn sound from a single remote vehicle, thereby increasing the ambient noise level.
The current invention describes a vehicle-to-vehicle signaling device for two-way communications that converts microwave warning messages sent by transmitting vehicles into control signals that are suitable for controlling devices that produce synthetic, intuitive sounds and displays in receiving vehicles. The sounds and displays are perceived by the drivers of receiving vehicles to be directed from the several directions and relative distances of transmitting vehicles. The range of a transmitted signal is confined to a limited distance around a transmitting vehicle by atmospheric absorption of the electromagnetic wave that carries the transmitted signal, and also by the transmitter power, which is set to a predetermined level. Receiving vehicles located beyond a limited distance from a transmitting vehicle do not react to the microwave warning messages due to the weakness of the signal. Vehicles that receive the microwave warning messages are also capable of transmitting microwave warning messages.
The purpose of the invention is to reduce the ambient noise level in the environment by reducing the noise produced by automobile horns and other audible vehicle-to-vehicle signaling devices, and also to improve the effectiveness of warning signals exchanged among vehicles.